In a wireless communication networks, there are communication nodes, for example base stations. Base stations normally comprise sector-covering antenna arrangements. Such an antenna arrangement comprises a number of antenna ports corresponding to branches for uplink and downlink, where downlink denotes transmission, TX, from the base station to other nodes such as mobile terminals, and uplink denotes reception, RX, to the base station from other nodes such as mobile terminals. A downlink branch is thus a TX branch and an uplink branch is thus an RX branch.
Normally a typical system configuration may comprise two TX branches in the form of transmission channels and two RX branches in the form of reception channels, but system configurations with two TX branches and four RX branches are more attractive since the additional two RX branches provide large uplink improvements for a relatively small cost and volume increase. However, two additional antenna ports are required in the antenna arrangement.
An even more complex antenna arrangement is required when two TX branches and four RX branches on a frequency band shall be combined with two TX branches and four RX branches from another frequency band. An example of such an antenna arrangement is disclosed in WO 2014/032740.
Due to a need for increased capacity, there is a desire for having two TX branches and four RX branches for three different frequency bands. WO 2014/086386 discloses an antenna arrangement having four TX branches and four RX branches for three different frequency bands. The disclosure of WO 2014/086386 comprises diplexers at an antenna subarray level i.e. several diplexers per antenna branch, which adds cost and weight.
There is thus a need for a less complicated compact antenna arrangement in a node, where the antenna arrangement has two TX branches and four RX branches for three different frequencies.